Autoimmune mice and stimulated normal mice make lambda 1 with increased V region diversity

Previous studies of the genetic bases of murine SLE have defined gene segments that encode the H chain and the kappa L chain of anti-DNA, anti-Sm, and anti-IgG autoantibodies. As a result of these studies, the genetic origins of autoantibody H chains and kappa L chains are better understood, but little remains known about the genetic bases of autoantibody lambda-chains. Thus, we have analyzed serologically the germ-line and somatic origins of lambda 1 L chains in antibodies of normal mice and in both antibodies and autoantibodies of autoimmune mice. This study finds an increased lambda 1 diversity in both Ag-stimulated mice and autoimmune mice. This study also finds that the lambda 1 L chains in antibodies of unstimulated normal mice have the gene segment-encoded variable region, V lambda 1. In contrast, additional genetic processes appear to make the lambda 1 V regions of antibodies in Ag-stimulated normal mice and the lambda 1 V regions of both antibodies and autoantibodies in autoimmune mice. The increased lambda 1 diversity that we found in both Ag-stimulated mice and autoimmune mice might be caused by mutational processes creating antibody diversities. Therefore, the same somatic processes might be able to make both antibody and autoantibody lambda 1 diversities.